The event module has one listing of 'products' that's used for any matches you configure.

It makes a 'snapshot' of that product and its price at the time you specify it for a shooter.

If you decide to change product prices and have already specified event items for some shooters, you'll need to refresh that price information (similarly to how the match registration makes a snapshot of a shooter's name, classification, etc.)

 

If you only have a to make changes for a few shooters, you can update them individually.  Click an shooter's item and click Change.

 

If you need to change an item or items for a number of shooters, click Refresh Prices and follow the wizard.